In the case of recent portable electronic devices, the formation of cases thereof from a metal having conductivity has tended to be increased. Thus, the need for the prevention of electrical defects inside and outside of electronic devices has increased.
In particular, for aesthetic purposes, strength improvements, and the like, cases in which entire external surfaces of portable electronic devices are manufactured using metal frames have increased. Thus, demand for means for protecting internal electronic components from external electrostatic discharge (ESD) or protecting users from electric shocks occurring due to internal short circuits has further increased.
However, as portable electronic devices have been miniaturized and have become highly integrated, separate ESD protection devices or electrical shock protection devices have become difficult to dispose therein.